From owner-freebsd-current Sun Mar 7 12:56:10 1999 Delivered-To: freebsd-current@freebsd.org Received: from frmug.org (frmug-gw.frmug.org [193.56.58.252]) by hub.freebsd.org (Postfix) with ESMTP id E3E3F14D2C for ; Sun, 7 Mar 1999 12:56:04 -0800 (PST) (envelope-from pb@fasterix.frmug.org) Received: (from uucp@localhost) by frmug.org (8.9.1/frmug-2.3/nospam) with UUCP id VAA06928; Sun, 7 Mar 1999 21:52:22 +0100 (CET) (envelope-from pb@fasterix.frmug.org) Received: (from pb@localhost) by fasterix.frmug.org (8.9.3/8.8.5/pb-19970302) id VAA03562; Sun, 7 Mar 1999 21:50:53 +0100 (CET) Message-ID: <19990307215053.A3517@fasterix.frmug.fr.net> Date: Sun, 7 Mar 1999 21:50:53 +0100 From: Pierre Beyssac To: Poul-Henning Kamp , Dave Mills Cc: Ollivier Robert , current@FreeBSD.ORG, Harlan Stenn , "David L . Mills" Subject: Re: NTP nanokernel support (experimental) References: <199903071351.aa20073@huey.udel.edu> <17044.920833790@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.92.8i In-Reply-To: <17044.920833790@critter.freebsd.dk>; from Poul-Henning Kamp on Sun, Mar 07, 1999 at 08:09:50PM +0100 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sun, Mar 07, 1999 at 08:09:50PM +0100, Poul-Henning Kamp wrote: > I don't think Ollivier is doing PPP/hardpps() yet, at least I have not > given him the semi-magic code needed for it :-) > > I wouldn't recommend trying it either, he is bound to have a >1 > msec jitter on the DCF77 waves at his place, and that is a lousy > diet for hardpps(). I agree; jitter with a low-cost DCF77 receiver is even more than that (5 to 10 ms). I tend to believe it's partly due to how the AM signal is demodulated and not that much from the location (Paris is not that far from Frankfurt after all). Maybe a lower jitter could be obtained by averaging 10 or 100 samples, I suppose that's how high-quality receivers work. This might be done in the ntpd driver. -- Pierre Beyssac pb@fasterix.frmug.org pb@fasterix.freenix.org {Free,Net,Open}BSD, Linux : il y a moins bien, mais c'est plus cher Free domains: http://www.eu.org/ or mail dns-manager@EU.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message